In general, once steroid use stops, the testicle begins regenerating lost tissue. Leydig cell counts often remain lower than original, suggesting that testosterone levels may be reduced in the long run. In practice, the longer period you used the steroid for (or the higher dose you used), the longer time you will need for your testicles to recover. Most men are able to recover most of the lost size but may notice that they don’t get quite back to the original size, a lower baseline testosterone level or permanently reduced sperm count. This is especially true for long term or high dose users.
Using Human chorionic gonadotropin (hCG) during or in-between cycles is a common practice among steroid users. The hCG, which mimics LH, is often used to avoid the negative feedback on LH and to restart testosterone production by testis. Use of hCG concurrently with TRT or steroid cycle may reduce impact of external androgens on testicular function.